The methods of direct current are broadly applicable, and are marketable in the investigations of the upper cross-section. They are distinguished by simplicity in fulfilling and high quality of information.
For implementing this method at IERP we employ the digital tools of SGS-VES system. The performance characteristics let the work to be executed with a high efficiency and accuracy. The software package is capable of conducting express analysis of the acquired material in field conditions.
Features of gauging equipment:
· Recording signals proceeds simultaneously from several electric lines;
· Registration of the feeding current form;
· Registering one sample/metering lasts 5 s;
· The registered parameters are loaded into DB and key blocks of binary files;
· Curve ρ? and table of parameters are computed in time of registration;
· The computed curves are saved into the file compatible with the quality registration program;
· The curve can be registered both with uncoiling and coiling of the array;
· Applying digital registration and processing signal of vertical electric sounding raises accuracy of value ρ? to 1 – 2 %;
· It is possible to receive a reliable signal dV at low MN and even with semi-separation ?? to be some hundred meters under moderate level of noise with supply voltage 12 V;
· Presence of long branches of curves obtained with minor MN lets precisely evaluate the mode of their scanning and more reliably define position of the medium curve VES;
· Calculation of ? with turned array provides additional information on the distribution of geoelectric heterogeneities of the upper cross-section over the profile.
In surveying by VES method we use a nonstandard grid of spacing ??/2 preset on condition of 12 counts per one decimal module. Such spacing is two-fold denser than that recommended by the regulations on electric sounding. However in this case a high density of measurements lets considerably raise accuracy of the materials obtained and correct VES curves complicated by geoelectric heterogeneities.